A nitrous solenoid uses 12 vdc to pull the valve plunger open (against spring pressure),
when the voltage is removed, the spring closes the plunger.

For the solenoid to stay open, there are three possibilities
1. voltage is staying on......not likely.
2. the plunger cannot move freely in the bore. Rust or debris is a possibility.
3. the spring may be broken.

It sounds as if the coil is pulling the plunger back, as it should, but something
is holding the plunger in the open position and the spring isn't strong enough to over come that resistance.

Solenoids are very simple to rebuild but you will need to make or purchase a spanner wrench to complete
teardown and reassembly.

I have a sneaking suspicion that I should have blown the new 6an line I got from summitt racing out with compressed air first...

Later this week I'm going to pull the 'noids and see what happened.

I've got a big nitrous filter about 2' down stream of the bottles after they Y fitting on the main -6 line. Is this optimal or should it be closer to the solenoid? Also does the orientation of it matter? Right now it's mounted vertically as I was thinking this would remove all the air and air pockets as I purged the line, but would like input.

Yes pump gas, but if the gas solenoid stuck closed on a 100 shot, I'd have blown the piss out of the engine from a lean condition....During the hit, it ran GREAT, I was only on it for a few seconds in 2nd gear from 20-50 so never got a look at the AFR. Im going to very closely inspect BOTH solenoids now! lol

It was after the run, with the clutch in, car in neutral, coasting, and foot off of the gas, it was idling right around 4300rpm! I freaked out, closed the main line solenoid (NOS brand) and held the purge open to vent the line ASAP. When I got stopped at the next light and the nitrous all vented, the car didnt want to idle for crap. (looooow AFR - car was adding fuel to the nitrous being inhaled around the closed throttle blade) However within 30 seconds she was back to normal...

Well I took them out and addressed a few small leaks whilst I was at it. Two little pieces of the stainless steel braid were pinned on top of the teflon insert on the plunger. I cleared that, then noticed that the plunger was quite difficult to index up and down. Blew that out, restretched the spring on the plunger, buttoned up the solenoid minus the coil, then smacked it a few good times to reform the seal on the teflon insert. Tested her, she worked perfect, then made 3 test runs with the psi around 600psi so I KNEW it would be rich. Worked like a champ!!

Now to run her up to 800psi and watch the AFR...if that checks out, then 950!

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